Empirical Equations for Levee Breach Parameters Based on Reliable International Data

Levee breach prediction and modeling requires an estimate of the breach characteristics, including the final breach width and lateral erosion rates. Currently, there are no widely accepted empirical equations for levee breach dimensions, lateral erosion rates, or breach development time. Previous empirical equations relied on limited, inaccurate, or incomplete data sets, including data from very old levee failures. In some cases, levees with specific features or levee failures governed by uncommon circumstances were included in equation development. The main objective of this study was to establish empirical equations to predict idealized levee breach geometric parameters for engineering analysis and design. The study process emphasized using reliable data from the relatively recent river levee failures and data from well-controlled physical model tests. Through research and personal contacts, I gathered and examined data for many international levee breaches. Data quality control identified reliable data sets that were more consistent with typical and expected field and design conditions. I applied further data control and correction, and finally selected
55 data sets for levee failures in the United States, France, Italy, Germany, Belgium, Dutch–Belgian border, China, and Japan. I used this data to develop empirical curves and equations for levee breach width and lateral erosion rates.

For each parameter, I provide the design level, the upper limit, and the lower limit curves and equations. The expected range of parameters can aid in better defining the range of flooding and damages to expect for levee failure. I also developed approximate equations for peak flow rate through levee breach by combining the weir flow equation with the new equations for the breach geometry. This paper includes all the resulting curves and empirical equations.